The present invention relates to ink cartridges and inkjet printers.
Generally, color inkjet printers use a plurality of color inks. These printers may include a plurality of separate color ink cartridges that are independently replaceable. This structure allows the ink cartridges to be consumed completely, thus reducing costs.
In an inkjet printer that uses the separate ink cartridges, a cartridge accommodating portion accommodates the ink cartridges. Each ink cartridge must be accurately located at a predetermined position of the accommodating portion. Further, since each ink cartridge corresponds to a different color, the cartridges must be aligned in the accommodating portion in a predetermined order.
Conventionally, a positioning member divides the cartridge accommodating portion into a plurality of chambers. The positioning member positions each ink cartridge in the corresponding chamber, thus installing the cartridge in the printer.
However, the positioning member complicates the structure of the cartridge accommodating portion. Further, the cartridge accommodating portion must have a clearance for receiving the positioning member, in addition to the cartridge chambers. This enlarges the cartridge accommodating portion.
In an inkjet printer described in Japanese Unexamined Patent Publication No. 4-185355, an accommodating recess is formed as the cartridge accommodating portion. Convex and concave portions are formed in the inner wall of the recess. Matching convex and concave portions are formed in the outer wall of each ink cartridge. That is, when each cartridge is received in the recess, the convex and concave portions of the cartridge engage with those of the inner wall of the recess. In this manner, the cartridge is positioned in the recess.
However, in this case, the convex and concave portions must be formed with a high accuracy such that each ink cartridge is positioned in the recess accurately and reliably. The forming of the convex and concave portions is thus complicated. Particularly, machining of the inner wall of the recess is complicated such that production efficiency decreases.
In an inkjet printer described in Japanese Unexamined Patent Publication No. 61-41553, a plurality of bead units are attached to a reciprocating carrier. Each head unit accommodates an ink container and includes an engaging projection and an engaging recess through which the head unit is connected to the adjacent head unit.
In this printer, each head unit accommodates a different color ink, and the head units must be aligned in a predetermined order. However, since these head units are identical, it is highly likely that the head units are aligned in an inaccurate order.
Accordingly, it is an objective of the present invention to provide an ink cartridge that is easily and accurately installed in a cartridge accommodating portion of an inkjet printer and has a simple structure to minimize the cartridge accommodating portion.
It is another objective of the present invention to provide an inkjet printer that includes the ink cartridge.
To achieve the foregoing and other objectives and in accordance with the purpose of the present invention, the invention provides an ink cartridge for an inkjet printer. The ink cartridge is one of ink cartridges that are detachably attached to a cartridge accommodating portion of the inkjet printer as aligned in parallel. Each ink cartridge has at least one engaging portion formed at a side of the ink cartridge that faces an adjacent ink cartridge. A set of the opposed engaging portions of each pair of adjacent ink cartridges forms a matching set in which the engaging portions engage with each other to position the adjacent ink cartridges with respect to each other. The matching sets are shaped and located such that a fitting structure between one pair of adjacent ink cartridges and a fitting structure between another pair of adjacent ink cartridges are different in form.
In another aspect of the present invention, each ink cartridge includes a contact that contacts one of connecting members formed in the cartridge accommodating portion when the ink cartridge is attached to the cartridge accommodating portion. Each contact is located offset from the middle of the associated ink cartridge in an aligning direction of the ink cartridges.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.